error-handling

问题 Angular2 has very useful promises error catching mechanism for chained promises. Yet, the usual case (at least for me) is that of promises called from within the resolve handler of the previous one. This is due to the need to process information prior to starting the next promise. For example: this.d( "facebookOAuthLogin() - starts" ); this.fbProvider.login().then( ( loginResponse: { status: string, authResponse: any, accessToken: string, expiresIn: string, session_key: string, sig: string,

问题 I wrote an R script which writes messages (progress report) to a text file. I modified the error option so that when an error occurs, the error message is also written to that file: options(error = function() { cat(geterrmessage(),file = normalizePath("logs/messages.txt"),append = TRUE) stop() }) It works, but I get this message in the console/terminal window when an error does occur: Error during wrapup: Execution halted So I'm thinking there's a better way to interrupt the execution of the

问题 I wrote an R script which writes messages (progress report) to a text file. I modified the error option so that when an error occurs, the error message is also written to that file: options(error = function() { cat(geterrmessage(),file = normalizePath("logs/messages.txt"),append = TRUE) stop() }) It works, but I get this message in the console/terminal window when an error does occur: Error during wrapup: Execution halted So I'm thinking there's a better way to interrupt the execution of the

问题 I'm trying to implement a try-catch block in scheme using (call-cc) method but i'm not sure how it can be used for that. I could not find any example. And found examples contains just error-handling but what i want to do is: if an error occurred, the scheme program has to give a message to user (via display for-example) without suspending the program. Is that possible? 回答1: Since you want to catch all errors, such as ones raised by both raise and raise-continuable you'd need both an exception

问题 I'm trying to implement a try-catch block in scheme using (call-cc) method but i'm not sure how it can be used for that. I could not find any example. And found examples contains just error-handling but what i want to do is: if an error occurred, the scheme program has to give a message to user (via display for-example) without suspending the program. Is that possible? 回答1: Since you want to catch all errors, such as ones raised by both raise and raise-continuable you'd need both an exception

问题 I'm trying to find a good article/examples of how DDD entities treat errors (and what would be considered exceptional errors and what wouldn't) and how they pass them up to the calling application layer (which usually wraps operations in a transaction that would need to be rolled back). Currently I'm thinking to consider all errors that would break the transaction of an aggregate (such as validation) to be exceptions. This way I can rollback the transaction in a "catch" block. For example:

问题 I am using a REST service to generate a CSV file that I want to prompt the user to download. An example of the service is below: https://localhost:8444/websvc/exportCSV?viewId=93282392 To prompt the user to download the file, I use this code: window.location.href = exportUrl , where exportUrl would be a URL like the one above. This works great if there are no errors on the server when executing the service. The file download prompt appears, the page doesn't refresh, and all is well. However,

问题 I am using a REST service to generate a CSV file that I want to prompt the user to download. An example of the service is below: https://localhost:8444/websvc/exportCSV?viewId=93282392 To prompt the user to download the file, I use this code: window.location.href = exportUrl , where exportUrl would be a URL like the one above. This works great if there are no errors on the server when executing the service. The file download prompt appears, the page doesn't refresh, and all is well. However,

问题 I have a validation class which uses method chaining. I would like to be able to do single checks with TRUE/FALSE like this: if ($obj->checkSomething()) {} But also chain methods like this: if ($obj->checkSomething()->checkSomethingElse()) {} The problem however is that if one method returns FALSE , it will not send back an object and thus breaks the method chaining which ends with this error: Fatal error: Call to a member function checkSomething() on a non-object in ... Do I have to pick

问题 When I type warnings() to console, I get back Warning message: In fread(my_directory, ... : C function strtod() returned ERANGE for one or more fields. The first was string input '4.40589099726375E-309'. It was read using (double)strtold() as numeric However when I type as.character(warnings()) , I get: [1] "fread(my_directory)" My objective is to get the actual message displayed in warning() into a character string, so that I can pass it to the logwarn function in the logging package.